It is common practice bottling the aforementioned liquid products in containers whose structure can be manufactured from multilayer or treated paper material, such as paperboard or cardboard coated with one or more layers of food-safe material suitable for liquid substances.
The containers in question are fashioned in most cases from flat blanks cut generally from a roll of material and folded as necessary along strategically placed crease lines to a shape suitable for holding a liquid product.
As a rule, such containers present a tubular structure of substantially square cross section.
The containers are manufactured using conventional machines which will bend the flat blank to fashion a tubular element presenting an open top end and an open bottom end.
First, mechanical arms are arranged for folding the edges of the open bottom end of the tubular element so as to close this same end. The resulting end folds are secured one to another by a heat seal effected with special plates positioned to engage selected areas of the folds.
The partially enclosed container is then filled with a liquid product directed in through the open top end. Thereafter, the top end is closed by bending the relative edges and securing the folds in same way as for the bottom end already described above.
Machines of the type in question present a notable drawback deriving from the fact that they are not equipped to handle containers of the type with a top end presenting a duct, identifiable typically as a tubular adapter or “neck” from which to pour the liquid contents and affording a mouth that can be closed by means of a suitable cap.
The neck fashioned generally in plastic material, must necessarily be anchored to the tubular body by heat sealing or welding operation in which the base of the neck is joined to the top edges coinciding with the open top end of the container. The particular position of the neck, which is centered on the longitudinal axis of the container, requires for its application an appreciable degree of precision.
Machines embraced by the prior art used currently to produce containers of the type in question are made up of particularly cumbersome and complex devices capable of dosing and sealing only one open end of the container.
More exactly, a first machine is applied to close the bottom end of the container, whereupon the partially closed container is transferred to a second machine that will close the top end together with the relative neck. Accordingly, the manufacture of one container involves the use of two different and separate machines, each designed to close and seal just one of the two open ends.
These machines present a major drawback deriving from the complexity of a manufacturing process in which the single container must pass from one machine to the other, with the result that the production costs and processing times involved become excessive.
Moreover, it will be appreciated that with two machines in operation, not only do the overall dimensions of the equipment become excessive, but there is also the significant drawback of having to provide a conveyor system, utilizing belts for example, such as will transfer the partially enclosed containers from one machine to the other.